Funny bumps on silver dollars

Greets all!

I have two rather small silver dollars with several bumps on their skin.
The bumps don't really look like warts, but instead are slightly tented
like a "zit". The best way I can think to describe their size and shape
is to imagine a 1mm beebee stuck under the skin on the sides of the
fish. Unfortuneately, I've no pictures of the creatures.

What I'm wondering is, has anybody seen something like this before? Does
it sound like something parasitic? I certainly cannot see any wound near
the bumps, or any anchor-worms or fish lice. The fish do not seem
bothered by it, and for all I know, they could simply be deformed.

Thanks in advance for any ideas as what this may be.

Regards,
Jesse Joe

p.s. Water conditions: No ammonia or nitrite. Nitrate 20-40ppm. Hardness
150ppm, alkalinity about 40 ppm, this is all according to the cheapie
test strips I have handy right now.

In article <j_e_s_s_e_j_o_e_-31936D.10423411052004 RemoveThis @news-int.gatech.edu>,
j_e_s_s_e_j_o_e_ RemoveThis @_y_a_k_.n_e_t says...
>
>Greets all!
>
>I have two rather small silver dollars with several bumps on their skin.
>The bumps don't really look like warts, but instead are slightly tented
>like a "zit".

I have three medium ones and they all have this as well. Been like this since
I got them a few months ago. Seem healthy otherwise.

Glenn